Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Klein-Gordon equation in quantum field theory is known to suffer from the possibility of negative probability. So, the question is, despite this, Klein-Gordon describes spin-zero field. So, how can negative probability and scalar field co-exist?

share|improve this question
    
More on Klein-Gordon equation and negative probabilities in quantum mechanics: physics.stackexchange.com/q/39224/2451 –  Qmechanic Oct 14 '12 at 18:20

1 Answer 1

up vote 2 down vote accepted

In QFT, we reinterpret the probability density as the probability charge density. In other words, negative probabilities correspond to antiparticles.

In fact, the Dirac equation which describes spin-1/2 also has this property, and it led to the prediction of the positron as the antiparticle of the electron.

share|improve this answer
    
but Wikipedia and physics.stackexchange.com/q/39224/2451 say that negative probability density do not make sense, and this is the reason for developing Dirac equation... So.. what is that and this? –  War Oct 14 '12 at 22:52
    
Yes, negative probabilities do not make sense. What physicists discovered was that they were not calculating the probability density, but ~ probability density * charge. So if charge is opposite, they get a negative answer, but the actual probability is positive definite. –  hwlin Oct 15 '12 at 0:25

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.